Timepiece escapement



Nov. 29, 1966 H. A. JOHNSON 3,287,897

TIMEPI ECE ESCAPEMENT Filed Aug. 4, 1965 5 Sheets-Sheet l INVENTORHAROLDAJOHNSON Nov. 29, 1966 H. A. JOHNSON 3,287,897

TIMEPIECE ESCAPEMENT Filed Aug. 4, 1965 i5 Sheets-Sheei 2 HAROLD JOHNSON,uw TORN Nov, 29, 1966 H. A. JOHNSON TIMEPIECE ESCAPEMENT .3Sheets-Sheet Filed Aug. 4, 1965 INVENTOR HAROLD JOHNSON United StatesPatent O 3,287,897 TIMEPIECE ESCAPEMENT v Harold Alec Johnson, LosAngeles, Calif., assignor to American Machine & Foundry Company, acorporation of New Jersey Filed Aug. 4, 1965, Ser. No. 477,205 10Claims. (Cl. 58-116) This invention relates to movements for clocks andwatches, and in particular to escapement mechanisms for use in the same.

The escapement mechanism as it exists in clocks and watches is a majorcause of their inaccuracy and high cost of manufacturing. This resultschiefly from the close dimensional requirements and the necessity foradherence to close tolerences especially with regard to the distancebetween axis of the escapement wheel and the axis of the escapementpawl.

It is therefore the main object of the invention to provide anescapement mechanism which eliminates the need for adherence to closetolerances and permits considerable departure from conventi-onaldimensional requirements without sacrificing the accuracy of the watch.

Another object of the invention is to provide an escapement mechanismhaving an escapement dog which is selectively movable or adjustable inrelation to the escapement axis.

Still another object of the invention is to provide an escapementmechanism having means to increase or decrease .the resistance in themovement of the escapement dog towards the escapement wheel.

A still further object of the invention is to provide a clock or watchwhich is relatively simple and inexpensive to assemble and tomanufacture without sacrice of accuracy or durability. A

These and other objects of the invention, as well as, certain featuresof novelty and advantages will be apparent from the followingdescription of an exemplary embodiment.

In the accompanying drawings illustrating the embodiment of theinvention:

FIG. 1 is a front elevation of a stop watch incorporating the invention;

FIG. 2 is a top View of the same, taken on line 2 2 of FIG. l;

FIG. 3 is a sectional rear view of the stop watch with the cover removedto illustrate its components;

FIG. 4 is a partial sectional side elevation taken on line 4 4 of FIG.3;

FIG. 5 is also a partial sectional side elevation taken on line 5 5 ofFIG. 3, illustrating the escapement mechanism on an enlarged scale;

FIG. 6 is another sectional side elevation taken on line 6 6 of FIG. 3;

FIG. 7 is an exploded view of the main drive gear and its clutchmechanism;

FIG. 8 is a partial sectional view of the escapement mechanism, taken online 8 8 of FIG. 5, illustrating the action of the escapement dog inconjunction with the escapement wheel, and;

FIG. 9 is a partial sectional view, similar to FIG. 8, illustrating amodified form of an adjustable escapement mechanism.

It should be understood at the outset that the present invention hasapplication in a wide variety of clock or watch movements as well as inrelated timing mechanisms. However, for the sake of brevity only, thepresrice ent invention will be shown and described in connection with astop watch. This example has been chosen since its principles andconcepts may be clearly observed.

Now with reference to the drawings, stop watch W consists of an outercasing or covering 10 in which is enclosed an inner housing 12supporting and containing the various clockwork components. As iscommon, the casing 10 and inner housing 12 are formed generally of afront shell or face and a rear shell or back. The parts of ythe innerhousing 12 are held together and spaced by a plurality of spacer screws50. The outer covering 10 has a front transparent face 18 and a backwhich is clipped inconventional fashion to the housing 12. The watch Wis provided with a stem or knob 20 normally situated at the 12 oclockposition.

With specic reference to FIGS. 3 5, the clock-work mechanism for drivingthe watch includes the knob 20 which is secured to the top end of asuitably shaped stem plate 22, .the upper end of which projects throughcutout portions 24 formed in the front and rear shell of the innerhousing 12, as well as in the watch case 10. The lower end of plate 22terminates in a hub` 26 rotatably supported by a transverse shaft or pin28, which is pivotally mounted in suitably formed bearings in the frontand rear wall of the inner housing 12. Adjacent to the hub 26 of sternplate 22 and, also, loosely supported by the shaft 28, there is locateda gear sector 30 which engages with a pinion gear 32 (FIG. 3). The gearsector 30 is provided with an extension arm 34 having a boss 36 carryingtwo spaced, horizontally projecting pins 38 (FIGS. 3 and 4). A torsionspring 40, constituting the main spring of the stop watch W, is woundloosely around the hub 26. One end of the spring 40 is lodged betweenthe projecting pins 38 and the other end of said spring is lodgedagainst a stationary pin 42 which is integral with and projectinghorizontally from the inner side of the front wall of the housing 12. Inaddition, housing 12 is provided with two additional pins 44 and 46which are similar to pin 42 and which are spaced apart from pin 42 andfrom each other so that the stationary end of the spring 40 can belodged against either of the three pins and thus provide means foradjusting the tension lof said spring 40.

Midway along the stem plate 22 is hooked one end of a tension spring 48,which has its other end anchored to one of the spacer screws 5l)separating the parts of the housing 12. The tension spring `48 servesthe purpose of keeping the stem 2G and plate 22 in the normal upright l2oclock position and returning it to this position after it has beencocked during winding operation which will be described hereinafter.

The indicator assembly and drive mechanism powered by the main spring`assembly previously described is shown clearly in FIGS. 6 and 7.Engaging with the gear sector 3) is a small pinion gear 32 fixedconcentrically to one face of a clutch disc 52. The other face of theclutch disc 52 is provided kwith a plurality of radial teeth 54, .asillustrated in FIG. 8. The clutch disc 52 is iixed on a stepped shaft 56projecting from both faces of the disc. Each end -of shaft 56 isrotatably supported in suitable bearings means provided in the front andrear inner faces of the housing 12. Adjacent to clutch disc 52 andloosely supported on the stepped shaft 56, is situated -a gear 58 havinga plurality of peripheral teeth. In addition, one face of gear 58 isprovided with a recess or shoulder 60 (FIG. 8) which is further providedwith a plurality of radial teeth 62 arranged in such a manner as toengage with and co-operate with the radial teeth 54 on the face ofclutch disc 52 when gear '58 is made to abut the disc 52. A collar 64 isfitted adjacent the other and smooth face of the gear 58 and is alsoloosely supported by the stepped shaft 56. The collar 64 is formed of ayieldable material such as sponge rubber or felt. A washer 66 completesthe assembly mounted on the stepped shaft 56 and acts as the spacerbetween the collar 64 and the inner side of the housing 12. The frontend of shaft 56 protrudes through the housing 12 and carries theindicator hand 16.

In operation, the watch W is wound by simply moving the stem 20 in acounterclockwise direction as indicated by the arrow D to the dottedline position of FIG. 4 and then releasing the same. The movement ofstem 20 is imparted to the gear sector 30 effecting a vwinding of thespring 40, through the engagement of the stem plate 22 on the side edge116 of boss 36 on the arm extension 34. Since gear sector 30 meshes withgear 32, which in turn is fixed on shaft 56, the anticlockwise rotationimparted to sector 30 effects a rotation of the shaft 56 thus carryingthe indicator hand 16 to its zero position.

Thus far, there has been described a simple clockwork movementsufficient to illustrate the construction of and function of theescapement of the present invention. For this purpose, reference is nowmade to FIGS. 3, 6, 8 and 9.

In FIG. 3 it will rbe seen that the peripheral teeth of the main gear 58mesh with a pinion 68 which is fixed to a larger gear 70. Both gears -68and 70 are Ifixed on a shaft 72 which is rotatably supported in suitablebearings means provided in the front and rear faces of housing 12. Gear70 meshes with still another pinion gear 74 fixed on a shaft 76 on whichis fixed still another wheel `78 which comprises the escapement wheel ofthe present mechanism. The shaft 76 is also rotatably supported at bothends in suitable bearing means provided in the front and rear innerfaces of the housing 12. The escapement wheel 78 comprises an innerperipherally geared member 80 and a concentric internally geared ringingmember 82 surrounding gear 80 and coplanar therewith in the fashion of asun and ring gear assembly. As illustrated in FIGS. 3 and 6', theperipheral teeth of gear 80` and the opposing teeth of ring gear 82 faceeach other with the apexes of one general-ly opposed to the valleys ofthe other and are so arranged as to provide an annular narrow path 81.Within path 81 there projects an escapement dog o1 finger 84. As shownin this embodiment, the escapement wheel, i.e. its two ring members areformed as one piece; however, as noted later, this is only one form andmay be conveniently fashioned of two or more pieces relatively fixed forunitary rotary movement.

Projecting escapement dog 84 is formed as part of a movable escapementdrum 86 mounted on a central stem or shaft 88, rotatably suported in abearing boss 90 on the inner surface of rear face of housing 12, andwhich acts as a fulcrum point for the drum 86. The front face 92 (FIG.5) of the boss 90 engages with the inner face of drum 86 and acts asretainer and an additional 'bearing for the latter. The escapement dog84 projects parallel to the axis 76 of the escapement wheel 78 from thefront face of drum 86 which is substantially parallel to the plane ofthe escapement wheel 78. The dog 84 is situated eccentrically withrespect to the fulcrum shaft 88 thus being able to oscil'late freelybetween the teeth of gears 80 and 82. In order to give betteroscillating performance, the drum might as shown be provided with anouter metal ring 96 for added weight.

It will be obvious that in operation, so long as the escapement drum 86is free t-o move, i.e, oscillate and the escapement wheel 78 is driventhrough the clockwork movement, the projecting dog 84 will cause thecontrolled and timed rotation of the escapement wheel 78 andconsequently, that of the main gear 58 and hand 16.

The stop watch W is also provided with a start and stop lever 100 whichprojects from an elongated slot 102 in the watch case (FIG. 3) and isintegral with an arcuate guide flange 104, which is slidably confined inthe peripheral lspace between the case 10 and housing 12. A curved lug106 projects from the lower side of flange 104 through a suitable slotin housing 12 and is provided with an arcuate tail 108. The free end ofthe tail 108 is formed into a stop lug or shoulder 110. Lug 106 is alsoprovided with a shaped hump 112 which engages the free end of a flexiblelock lever 114 projecting from and secured to one of the transversespacer screws 50.

In viewing FIG. 3 of the drawings, it is self-evident that when thelever is moved in a clockwise direction, the stop lug 100 wedges itselfbetween the inner peripheral wall of housing 12 and the periphery of theescapement drum 86, as illustrated in FIG. 3', and thus effecting alocking of the latter and preventing any movement 0f the same.

When lever 100 is moved in a counterclockwise direction, as indicated bythe arrow S, the stop lug is caused to ydisengage from the escapementdrum 86, the latter can then oscillate when urged by the escapement dog84 and wheel 78. The flexible lock lever 114 is employed 'for thepurpose of holding the lever 100 firmly in either the locked or unlockedposition.

Because gear 32 is connected to the remainder of the watch gearingthrough the ratchet-like clutch gearing members 52 and 58, operation ofthe watch is prevented so long as the stop lever 100 is in lockedposition. Of course, the clutch mechanism permits the return of stem 20,since after the stem 20 is pushed in counterclockwise direction to theend of the slot 24 as shown in dotted lines in FIG. 3, it automaticallysnaps back and returns to its 12 oclock position due to the action ofthe tension spring 48 attached to the stem plate 22. To preventundesired play and give greater sta-bility to the stern plate 22 duringwinding operation, the latter is provided with a ringshaped arcuateguide lug 118 which is concentric with the pivot point of said stemplate and slidingly engages with the inner `side of the peripheralportion of the housing 12.

In the escapement mechanism illustrated on an enlarged scale in FIG. 8,the escapement dog 84 has the shape of a diamond having four equalstraight sides and having two angles between them acute -and two obtuse.This shape has been found convenient. However, as will be seen in FIG.9, it is by no means to be understood as being the only shape. It hasbeen observed that dogs or fingers having round or oval cross-sectionalshapes, as well, are sufficiently successful. FIG. 8 furthermoreillustrates that the angles of the teeth of the ring gear 82 and theperipheral teeth o-f the gear 80 of the escapement wheel 78 may besubstantially the same and that the distance of the axis of the shaft 88of the carrier drum 86 and the escapement dog 84 is predetermined andfixed.

Notwithstanding this, the slope and pitch of the teeth are not criticaland may vary along with the shape of the dog. This, of course, givesemphasis to one of the chief advantages of the present invention, thatis, the dimensional limits of gear or dog are not critical thus enablingclock movements to be made easily and more cheaply than heretofore.Another advantage lies in the fact that by being able to vary thesefactors, a watchmaker may readily choose his timing Without being overlyconcerned with the criticality of his components.

In a modified embodiment of the escapement mechanism illustrated in FIG.9, another heretofore unknown feature can be seen in the design whichpermits various settings of the escapement dog 120 relative to the laxisor fulcrum pin 122 of the carrier member 124, in the case an ovalarm-shaped member, on which the said dog is fixed. The arm 124 which, ofcourse, replaces the dog carrying drum 86 shown in FIG. 7, is providedwith a plurality of spaced and longitudinally aligned holes 126, any oneof which may be engaged with the fulcrum pin 122 permitting shifting ofthe .axis of the arm 124 towards or away from the escapement dog 120 sothat when the dog is engaged with and moved by the teeth 128 and 130 ofthe escapement wheel 132, greater or lesser resistance may be generated.When the axis of the escapement arm 124 is brought closer to theescapement dog 120, it requires greater energy on the Ipart of theescapement wheel to move sai-d dog to and fro and thus effects a slowermovement of the escapement wheel 132 and consequently of the watchmechanism. When the distance -of the axis of the arm 124, relative tothe dog 120, is increased, the swinging angle of the latter is decreasedand it takes less energy to move the same which in turn results in afaster movement of the escapement wheel and the therewith convertedwatch mechanism. It can be readily seen that this arrangement makes itpossible to design an angle escapement mechanism adaptable for a numberof predetermined timings and specific applications.

In both the embodiment shown in FIGS. 8 or 9, it will be observed thatthe fulcrum axis of the carrier member is parallel to the axis of theescapement wheel and it intersects the plane of the escapement wheelwithin the space or area :between the teeth of the gear members. Thisfacilitates oscillation of the dog or finger.

In conventional escapement mechanisms, the dimensional limits between,for example, the axis shaft 88 of the escapement drum 86 and the axisshaft 70 of the escapement wheel 78 are extremely critical and requirethe observance of a close tolerance, the present invention entirelyeliminates this need and permits slackening of this dirllensionalrequirement to a degree not heretofore poss1 e.

The embodiments of the present invention as shown in the drawings aremerely illustrative. Many other forms, all within the scope of thepresent invention, can be fashioned for both the coplanar escapementwheel assembly and/ or escapement dog. These embodiments will seemobvious now that the concept has been taught, nevertheless, the innerand outer coplanar gear members can be molded in integral forms, Iasshown, or machined, stamped or assembled of separate parts in eithermetal or plastic. The escapement dog may also take various shapesincluding round, oval, square or multilateral. As to the teeth on thegear members, their shape may take various forms, (as shown) eitherhaving acute or more obtuse angles, sharp or flat top etc. It is seenapparent that one or more of the elements, (dog, teeth, etc.) may bevaried, the only criterion to be concerned with being the over-allgeometry permitting the dog to oscillate between the teeth at apredetermined timing.

It will also be `apparent that the present invention need not beconfined to use in stop watch (as described for illustration) but in anywatch movement.

While we have shown the invention in the best forms known to us, it willnevertheless be understood that this is purely exemplary and thatmodifications in the construction, arrangement and combination of partsand the substitution of equivalents, mechanically and otherwise, may bemade without departing 'from the spirit of the invention, except as itmay be limited in the appended claims.

What is claimed is:

1. A timing escapement mechanism comprising a pair of coplanar spacedconcentric gear members one of which comprises a wheel gear having aplurality of peripheral teeth and the other of which comprises a ringgear having a plurality of internally facing teeth, and a dog locatedbetween the inner and outer gear members adapted to oscillate betweensaid teeth.

2. A timing escapement mechanism comprising a pair of driven coplanarconcentric gear members one of which comprises a wheel gear having aplurality of peripheral teeth andthe other of which comprises a ringgear having a plurality 4of internally facing teeth, and a freelypivotal follower dog located between the inner and outer gear membersadapted to oscillate between the teeth of said two driven gear members.

3. A timing escapement comprising a pair of relatively fixed coplanarconcentric gear members one of which comprises a wheel gear having aplurality of peripheral teeth and the other of which comprises a ringgear having a plurality of internally facing gear teeth, said relativelyfixed gear members being as a unit freely rotatable about a fixed axisand a driving dog located between the inner and outer geant members,said dog being adapted to oscillate between the teeth thereof, and drivemeans for oscillating said drive dog thereby causing said relativelyfixed gear members to effect a periodic rotary movement about its fixedaxis.

4. In a clock or watch movement, an escapement mechanism comprising apair of relatively fixed annularly spaced coplanar concentric gearmembers one of which comprises a wheel gear having a plurality ofperipheral teeth and the other of which comprises a ring gear having aplurality of internally facing gear teeth, said relatively fixed gearmembers being as a unit rotatable about their common central axis, and adog located within the annular space between said gear members, said dogbeing pivotally mounted to oscillate between the teeth of said gearmeans, and means co-operating with said clockwork movement for drivingeither said gear members or said dog to thereby effect a periodic rotarymovement of said gear members.

5. In a clock or watch movement, an escapement mechanism comprising apair of relatively fixed annularly spaced coplanar concentric gearmembers one of which comprises a wheel gear having a plurality ofperipheral teeth and the other of which comprises a ring gear having aplurality of internally facing gear teeth, said relatively fixed gearmembers being as a unit Irotatable about their common central axis, anda follower dog located within the annular space between said gearmembers, said dog being mounted to pivot about an axis remote from saiddog, and means co-operating with said clockwork movement for drivingeither said gear members or said dog to thereby effect a periodic rotarymovement of said gear members.

6. In a clock or watch movement, an escapement mechanism comprising apair of relatively fixed annularly spaced coplanar concentric gearmembers one of which comprises a wheel gear having a plurality ofperipheral teeth and the other of which comprises a ring gear having aplurality of internally facing gear teeth, said relatively fixed gearmembers being rotatable as a unit about their common central axis, and afollower dog located within the annular space between said gear members,said dog being pivotally mounted to pivot about an axis remote from saiddog, means for selectively varying the distance between said dog and thepivot axis, and means co-operating with said clockwork movement fordriving either said gear members or said dog to thereby effect aperiodic rotary movement of said gear members.

7. In a clock or watch movement an escapement mechanism comprising awheel member rotatably mounted about its central axis, said Wheel memberhaving formed in one face thereof a pair of spaced concentric gearmembers, one of said gear members having a plurality of peripheralteeth, the other of said gear members having a plurality of linternalteeth opposing those of said one member, carrying means located adjacentsaid one face of said wheel member, nger means projecting from saidcarrier means into the space between the teeth of said gear members,said carrier means being pivotably mounted about an axis parallel to theaxis of said wheel member to permit said finger to move within the spacebetween said gear members, means for driving either said wheel member orsaid carrier member to effect periodic rotary movement and oscillationof said finger.

8. The mechanism in accordance with claim 7, wherein said carrier meanscomprises a second wheel member disposed in a plane parallel to theplane of'the first wheel member and is pivotable about its central axis,the projecting finger being located in a position radially remote fromsaid central axis and substantially parallel thereto. References Citedby the Examiner 9. The mechanism in accordance with claim 7, whereinFOREIGN PATENTS the carrier means includes means for selectivelypositioning the finger `radially of said axis. 5791722 6/1933 Germany'10. The mechanism in accordance with claim 7, where- 5 in the axis ofthe carrier means intersects the plane of RICHARD B' WILKINSON Prlmary.Exammer' the Wheel member in the space between the gear members. GERALDF. BAKER, Examiner.

1. A TIMING ESCAPEMENT MECHANISM COMPRISING A PAIR OF COPLANAR SPACEDCONCENTRIC GEAR MEMBERS ONE OF WHICH COMPRISES A WHEEL GEAR HAVING APLURALITY OF PERIPHERAL TEETH AND THE OTHER OF WHICH COMPRISES A RINGGEAR HAVING A PLURALITY OF INTERNALLY FACING TEETH, AND A DOG LOCATEDBETWEEN THE INNER AND OUTER GEAR MEMBERS ADAPTED TO OSCILLATE BETWEENSAID TEETH.